Arduino的教學03-讀取光敏電阻與序列埠輸出

一、教學目標：利用光敏電阻控制 LED燈：

http://yehnan.blogspot.tw/2012/02/arduino_23.html

二、接線圖

三、程式碼

int photocellPin = A0; // 光敏電阻 (photocell) 接在 anallog pin A0
int photocellVal = 0; // photocell variable
int minLight = 600;   // 最小光線門檻值
int ledPin = 13;
int ledState = 0; 
 
void setup() {
  pinMode(ledPin, OUTPUT); 
  Serial.begin(9600);
}
 
void loop() {
  // 讀取光敏電阻並輸出到 Serial Port 
  photocellVal = analogRead(photocellPin);
  Serial.println(photocellVal);   
  
  // 光線不足時打開 LED
  if (photocellVal < minLight && ledState == 0) {
    digitalWrite(ledPin, HIGH); // turn on LED
    ledState = 1;
  }
  
  // 光線充足時關掉 LED
  if (photocellVal > minLight && ledState == 1) {
    digitalWrite(ledPin, LOW); // turn off LED
    ledState = 0;
  }  
  
  delay(100);       
}

練習-01-加入序列埠的除錯(serial moniter)

int photocellPin = A0; // 光敏電阻 (photocell) 接在 anallog pin A0
int photocellVal = 0; // photocell variable
int minLight = 800;   // 最小光線門檻值
int ledPin = 13;
int ledState = 0; 
int no=0; 
void setup() {
  pinMode(ledPin, OUTPUT); 
  Serial.begin(9600);
}
 
void loop() {
  // 讀取光敏電阻並輸出到 Serial Port 
  photocellVal = analogRead(photocellPin);
   no++;
   Serial.print("test:");   
     Serial.print(no);
     Serial.print(":"); 
  Serial.println(photocellVal);   
 
  
  // 光線不足時打開 LED
  if (photocellVal < minLight && ledState == 0) {
    digitalWrite(ledPin, HIGH); // turn on LED
    ledState = 1;
  }
  
  // 光線充足時關掉 LED
  if (photocellVal > minLight && ledState == 1) {
    digitalWrite(ledPin, LOW); // turn off LED
    ledState = 0;
  }  
  
  delay(100);       
}

四、作業練習
1.請設定當光敏電阻的測量值小於設定值時亮紅色LED燈，否則亮綠燈。